Headlight Gremlin

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03 Dec 2010 05:46 #2211 by timberhollow9310
Noticed a strange issue tonight when driving my '87 928.

With the engine running the pop up headlights will not deploy.

When the engine is off I can turn on the headlights by turning the ignition key to the pre-start position....they pop up fully lit.

However, as soon as I start the engine the headlights go out, while remaining in the up position (unless turned off).

I did this several time to verify and got the same results over and over.

My main mechanic suggested that I start by replacing the headlight relay switch, however I thought I would check here also to see if anyone had a suggestion/thought or suggestion on this issue.

I almost never drive it a night, but I see no reason why this is happening, as all system appear functional…just not at the proper time!

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03 Dec 2010 06:18 #2212 by adminVB
Replied by adminVB on topic Headlight Gremlin
(moved from technical library to technical discussion)

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03 Dec 2010 09:14 #2213 by 928mac
Replied by 928mac on topic Headlight Gremlin
I think your mechanic may be right but I am not sure.
My first thought was that the run circuit dose not have power to your light module but the accessory circuit dose.
So it could be a fuse or a relay but I am not even sure if there is a different fuse between the two circuits so it may be a relay like he says.
I am sorry that I am not more help as I am at the office and do not have access to the manual.

Brad

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03 Dec 2010 10:05 #2214 by timberhollow9310
Replied by timberhollow9310 on topic Headlight Gremlin

I think your mechanic may be right but I am not sure.
My first thought was that the run circuit dose not have power to your light module but the accessory circuit dose.
So it could be a fuse or a relay but I am not even sure if there is a different fuse between the two circuits so it may be a relay like he says.
I am sorry that I am not more help as I am at the office and do not have access to the manual.

Brad

Thanks Brad. I ordered the relay this morning as that seems the likely issue. Since the headlights work normally up until I hit the ignition I discounted the fuse. However there may be some sort of short being transmitted at ignition activation. Just guessing now.

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03 Dec 2010 14:25 #2216 by pcar928fan
Replied by pcar928fan on topic Headlight Gremlin
Do that but keep in mind your car is of the correct vintage to have a failing ignition switch too... When those fail VERY STRANGE things happen to these cars. It is CRAZY the kind of things that go on when that switch dies. So, you might start the car and then turn the key back (like you are turning the car off) just a little bitty bit and see if that changes anything... That is what you can do for a little while in the early stages of this failure.

Good luck and I hope it is just an easy relay fix!

James
78 Silver / Black-white #295
84 Ruby Red / Black AO84
88 Dark Blue / Linen-Black
92 Polar Silver / Dark Blue 92EURO
93 Arrow Blue / Black

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03 Dec 2010 16:35 #2225 by timberhollow9310
Replied by timberhollow9310 on topic Headlight Gremlin

Do that but keep in mind your car is of the correct vintage to have a failing ignition switch too... When those fail VERY STRANGE things happen to these cars. It is CRAZY the kind of things that go on when that switch dies. So, you might start the car and then turn the key back (like you are turning the car off) just a little bitty bit and see if that changes anything... That is what you can do for a little while in the early stages of this failure.

Good luck and I hope it is just an easy relay fix!

Thanks James. Tried your suggestion, but no go. Once the ignition is turned to start the lights go out (stay up) and don't come back on until I recycle the ignition back to pre-start position. Forgot to mention, this vehicle has been a garage queen with collectors and had the best of maintenance (less than 40K miles). Minor problem, but thanks for the help.
Ed

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03 Dec 2010 18:14 #2231 by 928mac
Replied by 928mac on topic Headlight Gremlin

Thanks James. Tried your suggestion, but no go. Once the ignition is turned to start the lights go out (stay up) and don't come back on until I recycle the ignition back to pre-start position. Forgot to mention, this vehicle has been a garage queen with collectors and had the best of maintenance (less than 40K miles). Minor problem, but thanks for the help.
Ed


Can you put your car year and details in your sig so that we all can help with the correct year info.

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03 Dec 2010 21:07 #2235 by Kiln_Red
Replied by Kiln_Red on topic Headlight Gremlin
Relay, relay, relay.

Same exact symptoms I had once. Replaced the relay, fixed the problem. James is right also. A failing ignition switch will show similarly crazy symptoms. I would expect more trouble on a number of other functions if it were when terminal 50 (starter circuit) was energized if the ignition switch were suspect.

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03 Dec 2010 23:46 #2237 by pcar928fan
Replied by pcar928fan on topic Headlight Gremlin
Austin,

I had all kinds of strange stuff when my S4 ignition went bad. A strange click behind the dash when you would hit the brakes. Brake lights would not come on and the warning could not be canceled. I can't remember the other stuff but there were a couple of other non-brake related crazy things that happened too!

James
78 Silver / Black-white #295
84 Ruby Red / Black AO84
88 Dark Blue / Linen-Black
92 Polar Silver / Dark Blue 92EURO
93 Arrow Blue / Black

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04 Dec 2010 05:12 #2240 by timberhollow9310
Replied by timberhollow9310 on topic Headlight Gremlin

Relay, relay, relay.

Same exact symptoms I had once. Replaced the relay, fixed the problem. James is right also. A failing ignition switch will show similarly crazy symptoms. I would expect more trouble on a number of other functions if it were when terminal 50 (starter circuit) was energized if the ignition switch were suspect.

Thanks everyone for help on this. Is there anything difficult or concerning about replacing a relay? Is it necessary to disconnect the battery? Would it be a good idea to clean out the relay box and spray with an electrical spray while I am in there? Have good weekend all.

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04 Dec 2010 11:57 #2244 by Kiln_Red
Replied by Kiln_Red on topic Headlight Gremlin
Shouldn't take more than a couple of minutes. Sometimes the most difficult part is just simply removing the old relay from its socket as it can be rather stuck. Cleaning the grounds above the CE board may be a good idea while you're in there. There are two. Each of the bolts securing the wires to the firewall are 10mm, I believe.

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04 Dec 2010 16:09 #2250 by pcar928fan
Replied by pcar928fan on topic Headlight Gremlin
I can't get most of the relay's OUT of my cars! They are stuck in there so good. I thought there was some trick to it...there is a "relay puller" but I think it is not much more than a glorified bottle opener. ;)

James
78 Silver / Black-white #295
84 Ruby Red / Black AO84
88 Dark Blue / Linen-Black
92 Polar Silver / Dark Blue 92EURO
93 Arrow Blue / Black

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